specific diseases require a local treatment of the skin by cold or heat, or a treatment under controlled temperature variations with a big cooling power. Because the main purpose of the probe is to cool, we will discuss mainly the cooling aspect. Cold is up to now one of the oldest and most frequently used means in the treatment of acute musculoskeletal injuries. It gives, according to various authors, the following advantageous effects:
1) Increase of blood circulation (Travell, J., Simons, D.: Myofascial Pain and Dysfunction, The Trigger point manual, volume 1 & 2, Williams and Wilkins) PA1 2) Increase of articular mobility (Nielson, A. J.: Spray and stretch for relief of myofascial pain. Physical Therapy, 58, 567-569, 1978) PA1 3) Diminish inflammation (Schmidt, K. L., e.a.; Heat, cold and inflammation, Zeitschrift fur Rheumatologie, 38, 391-404, 1979) PA1 4) Diminish oedema (Meeusen R. e.a.: Cryotherapy in sportmedicine--the effect of topical ice application on the permeability of the lymphvessels, Sports and Medicine, McGregorand Moncur, 246-250, 1986) PA1 5) Increase of muscular relaxation (Clenendi, N. M. A. and Czumski, A. J.: Influence of cutaneous ice application on single motor units in humans. Physical Therapy, 51, 166-175, 1971) PA1 6) Diminish muscular spasms (6) (Lee, J. M. and Warren, M. P.: Cold Therapy in rehabilitation, Belt & Hymen, London 19978) PA1 7) Diminish pain (Grant, A. E.: Massage with ice in the treatment of painful conditions of the musculoskeletal system, Arch. Phys. Med. Rehab., 44, 233-238, 1964) PA1 8) Breaking the pain and spasm cycle (8) (Oison, J. E. and Stravino, V. D.: A review of cryotherapy. Physical Therapy, 53, 53, 840-853, 1972) PA1 from the cold side of the Peltier module to the cooling head; and, PA1 from the hot side of the Peltier module to the heat dissipating element.
In the past, cold therapy or cryotherapy has often been applied by means of ice cubes, within or without a housing, e.g. a waterproof pocket or a cup. At the same time, pockets containing a specific gel were offered for sale. These were cooled in a cooling space. Thereafter, they were applied to the skin. Alternatively, cold air was blown, via a cooling system, on the skin of a part of the body. Another method is the application of very volatile substances having a low boiling point, such as ethylchloride and/or fluorimethane. These are CPKs and are harmful for ozone and poisonous for human beings. Their use has been forbidden in certain states of the USA due to these reasons.
All above mentioned systems have the problem that temperature control of the cooling medium and the treated surface is very poor, or even impossible. Also the cooling power by other media is too low to be therapeutically significant.
The problem is thus to develop a system by which the heat production or heat dissipation can be controlled continuously and by a sufficient power. This allows to substitute ice and has the advantage that it may be designed in a handy form for use, see FIG. 13).
U.S. Pat. No. 4,519,389 describes a cryoprobe for freezing the eye-lens during surgery. This cryoprobe consists of a small Peltier element. The cold side is in direct contact with the eye-lens. The hot side is mounted on a heat dissipating element, which may be used as an electrical conductor. The heat dissipating element is cooled by the environmental atmosphere or by contacting the hand of the physician.
Although this type of cryoprobe is suitable for cooling small surfaces, such as an eye-lens, it is not suited for cooling larger bodies such as good circulated skin, musculi and other underlying tissues.
On the one hand it is impossible for one Peltier element, mounted this way, to provide the required heat transport. On the other hand it is impossible that this amount of heat, released by the part of the body, can be dissipated by the environmental air, unless its flow is substantially forced. At the same time, the heat that is removed, must be conducted suitably through the cryoprobe, such that the environment does not unwantedly undo a portion of the useful heat transport.
Also in the patent U.S. Pat. No. 3,207,159, U.S. Pat. No. 4,585,002, U.S. Pat. No. 4,860,748, U.S. Pat. No. 3,133,539, U.S. Pat. No. 3,168,895, U.S. Pat. No. 4,915,108, EP-A-0 552 379 and EP-A-0 651 308, Peltier elements are used to cool the skin. However, none of the embodiments therein have a useful cooling capacity comparable to the capacity of ice frictions.